Is insect repellent safe during pregnancy?

The verdict

Yes, and this is one of the few pregnancy questions where the guidance actively pushes you towards the chemical rather than away from it.

The UK's National Travel Health Network and Centre states that because malaria is a serious disease in pregnancy, DEET-based repellents in concentrations up to 50% are recommended for all pregnant women, at any stage of pregnancy, travelling to areas where malaria or other insect-borne diseases are a risk. It adds that avoidance of mosquito bites is extremely important in pregnancy, because pregnant women are particularly attractive to mosquitoes.

ACOG's travel guidance says the same thing more briefly: use EPA-registered bug spray with DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol, and used as directed these sprays are safe to use while pregnant or breastfeeding.

The reasoning is a comparison, not a clean bill of health. Malaria, Zika, dengue and Oropouche in pregnancy carry consequences that a repellent does not.

What the evidence on DEET actually shows

TravelHealthPro summarises it directly: DEET has been used as an insect repellent for more than 50 years, and a number of studies have concluded that the risks of adverse effects are low for all groups, including infants, children, and pregnant and breastfeeding women, when applied according to the product instructions.

It cites the specific pregnancy evidence too. The use of 20% DEET during the second and third trimesters was not associated with adverse effects on the infants in pregnancies followed for up to 12 months after birth.

One practical fact is worth knowing before you buy the strongest bottle on the shelf: there is no further increase in duration of protection beyond a concentration of 50%. Higher numbers on the label buy you nothing. What higher concentration does buy, up to that point, is longer protection between applications rather than better protection at any moment.

The alternatives, ranked

If DEET is not tolerated or not available, TravelHealthPro names three alternatives to be used at the highest strength available: icaridin, also called picaridin, which has repellent properties similar to DEET with comparable duration when both are used at 20%, and which should be at least 20% if used against malaria; eucalyptus citriodora oil, hydrated, cyclized, previously known as PMD, which is effective but shorter-acting; and IR3535, which also has a shorter duration against Anopheles mosquitoes and so needs more frequent application.

It is candid about the gap in the evidence for these: there is no data concerning exposure to icaridin or eucalyptus citriodora oil in human pregnancy, although animal studies have not demonstrated maternal or developmental toxicity. In other words, the alternatives are less well studied in pregnancy than DEET is, which is the opposite of what most people assume when they reach for the gentler-sounding option.

How to use it

• Apply to exposed skin, even if your clothing has been treated. Repellent on clothes does not protect the skin that is showing.
• Sunscreen first, then DEET. DEET reduces the protection of sunscreen, so apply the sunscreen first and use SPF 30 to 50 to compensate. There is no evidence that sunscreen reduces the effectiveness of DEET above 33%.
• Reapply more often than the label suggests. Travellers typically apply around half the amount at which a product was tested, and sweat, humidity and swimming all remove it. Reapply when the mosquitoes start taking an interest.
• Not on cuts or irritated skin, and not directly onto the face. Apply to your hands first, then to your face, avoiding lips and eyes.
• Wash it off with soap and water when you no longer need it.
• Mind your kit. DEET can melt synthetic fibres and damage plastics, though it does not harm wool, linen or cotton.

Repellent is not the whole strategy. TravelHealthPro and the CDC both emphasise long sleeves and trousers, permethrin-treated or pre-treated clothing, air-conditioned or screened rooms, and sleeping under a long-lasting insecticide-treated net with a mesh no larger than 1.5mm. The NHS gives the same three-part advice for pregnancy: a repellent recommended for use in pregnancy, covering skin from dusk until dawn, and always sleeping under a mosquito net.

The destination question comes first

Before any of this, both countries would rather you did not go. The NHS advises that if possible you should avoid travelling to malarial areas while pregnant, and that it is not recommended to travel to parts of the world where Zika is present. ACOG says pregnant travellers should avoid travel to areas with an active CDC Zika travel health notice, and that you should not travel to areas with malaria risk.

If the trip cannot be avoided, the NHS notes that antimalarial tablets are available and that the risk of harm from malaria is likely to be much greater than any potential risk from the medicine, but that the choice depends on the country, your stage of pregnancy and your medical history. That is a GP or travel clinic conversation, and it is a medication question rather than a repellent one.

Where guidance genuinely differs

The UK permits 50% DEET; Canada's ceiling is 30%. This is the sharpest divergence in this batch. TravelHealthPro recommends DEET up to 50% for all pregnant women at any stage. Health Canada states that the right concentration of DEET for adults and children older than 12 is up to 30%, with lower limits for younger children and no DEET at all for infants under six months. Canada's limit is a registration ceiling applying to everyone rather than a pregnancy-specific restriction, but the practical effect is that a product a UK travel clinic recommends in pregnancy is not sold for adult use in Canada.

The US names a list rather than a number. ACOG and the CDC point to EPA-registered products containing DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol, and say these are safe in pregnancy when used as directed, without publishing a maximum concentration for pregnant users.

Only Canada addresses treated clothing for pregnancy explicitly. Health Canada states that adults, including pregnant women, may wear permethrin-treated clothing, and adds that permethrin-treated clothing is not available for children under 16. That is a clearer statement than either UK or US guidance offers on the same point.

Age limits for infants differ too, which matters if you are travelling with an older child. UK guidance permits up to 50% DEET in babies and children over two months. Health Canada permits up to 10% from six months and nothing below that. If you buy repellent for the family in one country and use it in another, you are following two different rulebooks.